package com.leonzhangxf.ioc.transaction;

import net.sf.cglib.proxy.Enhancer;
import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

/**
 * @author 应癫
 * <p>
 * <p>
 * 代理对象工厂：生成代理对象的
 */
public class ProxyFactory {

    private TransactionManager transactionManager;

    public void setTransactionManager(TransactionManager transactionManager) {
        this.transactionManager = transactionManager;
    }

    /**
     * Jdk动态代理
     *
     * @param obj 委托对象
     * @return 代理对象
     */
    public Object getJdkProxy(Object obj) {

        // 获取代理对象
        return Proxy.newProxyInstance(obj.getClass().getClassLoader(), obj.getClass().getInterfaces(),
            new InvocationHandler() {
                @Override
                public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                    Method objMethod = obj.getClass().getMethod(method.getName(), method.getParameterTypes());
                    Transactional transactional = objMethod.getAnnotation(Transactional.class);
                    if (null == transactional) {
                        return method.invoke(obj, args);
                    }

                    Object result;
                    try {
                        // 开启事务(关闭事务的自动提交)
                        transactionManager.beginTransaction();
                        result = method.invoke(obj, args);
                        // 提交事务
                        transactionManager.commit();
                    } catch (Exception e) {
                        e.printStackTrace();
                        // 回滚事务
                        transactionManager.rollback();
                        // 抛出异常便于上层servlet捕获
                        throw e;
                    }
                    return result;
                }
            });

    }


    /**
     * 使用cglib动态代理生成代理对象
     *
     * @param obj 委托对象
     * @return proxy obj
     */
    public Object getCglibProxy(Object obj) {
        return Enhancer.create(obj.getClass(), new MethodInterceptor() {
            @Override
            public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
                Method objMethod = obj.getClass().getMethod(method.getName(), method.getParameterTypes());
                Transactional transactional = objMethod.getAnnotation(Transactional.class);
                if (null == transactional) {
                    return method.invoke(obj, objects);
                }

                Object result;
                try {
                    // 开启事务(关闭事务的自动提交)
                    transactionManager.beginTransaction();
                    result = method.invoke(obj, objects);
                    // 提交事务
                    transactionManager.commit();
                } catch (Exception e) {
                    e.printStackTrace();
                    // 回滚事务
                    transactionManager.rollback();
                    // 抛出异常便于上层servlet捕获
                    throw e;
                }
                return result;
            }
        });
    }
}
